Impact-modified blends of polycarbonate are known. Also known are flame resistant polycarbonate compositions where the flame retarding agent is halogen-free.
The relevant art is noted to include JP 2001 031 860 that disclosed an impact strength composition, said to be hydrolytically stable and chemically resistant, containing polycarbonate, a graft elastomer having a core-shell structure and red phosphorus.
An impact modified thermoplastic molding composition containing polycarbonate and a graft (co)polymer wherein the graft base includes a rubber selected from a group that includes silicone-acrylate composite has been disclosed in U.S. Pat. No. 7,067,567. The graft (co)polymer is exemplified by methyl methacrylate-grafted silicone-butyl acrylate composite rubber. An impact resistance composition containing polycarbonate and graft polymer based on a silicone-butyl acrylate composite rubber is disclosed in U.S. Pat. No. 4,888,388.
A flame retardant, chemically resistant and thermally stable composition containing a halogenated aromatic polycarbonate resin, aromatic polyester resin, and graft rubber polymer composite is disclosed in JP 04 345 657. The graft rubber is said to be obtained by grafting vinyl monomer(s) onto rubber particles consisting of a poly-organosiloxane rubber and a polyalkyl (meth)acrylate rubber entangled so as not to be separated from each other.
JP8259791 is considered to disclose a flame-retardant resin composition said to feature excellent impact resistance and flame retardance and containing polycarbonate resin with a phosphoric ester compound and a specific composite-rubber-based graft copolymer. The composite-rubber-based graft copolymer is obtained by grafting at least one vinyl monomer (e.g. methyl methacrylate) onto a composite rubber that contains 30-99% polyorganosiloxane component and 70-1% of poly alkyl (meth)acrylate rubber component.
JP 7316409 disclosed a composition having good impact resistance and flame retardance containing polycarbonate, phosphoric ester and a specified graft copolymer based on a composite rubber. The graft copolymer is obtained by graft polymerization of one or more vinyl monomers onto a composite rubber in which polyorganosiloxane component and polyalkyl (meth)acrylate rubber component are entangled together so as not to be separable.
U.S. Pat. No. 4,824,723 disclosed a flame retardant material that contains polycarbonate and a flame retardant. Phosphorous compounds alone or in combination with zinc salt is referred to among the disclosed flame retardants.
U.S. Pat. No. 4,963,619 disclosed a thermoplastic polycarbonate molding composition containing polycarbonates, siloxane-containing graft polymers and, optionally, other thermoplasts and/or standard additives. The composition is said to feature high toughness, particularly at low temperatures.
U.S. Pat. No 6,423,766 disclosed a flame-retardant polycarbonate resin composition, containing polycarbonate resin, a composite rubbery graft copolymer, a halogen-free phosphoric ester and polytetrafluoroethylene. The composition is said to exhibit improved mechanical properties, moldability, flowability, and flame retardance. The graft rubber is based on polyorganosiloxane rubber component and polyalkyl acrylate rubber component and the two components are inter-twisted and inseparable from each other. The grafted rubber is grafted with one or more vinyl monomers.
A flame retardant resin composition containing polycarbonates, a halogenated flame-retardant, and a rubber-occluded flame retardant synergist has been disclosed in U.S. Pat. No. 4,339,556. Zinc borate is disclosed among the suitable flame retardant synergists.
A flame retardant polycarbonate composition exhibiting reduced heat release rate has been disclosed in U.S. Pat. No. 5,153,251. The composition contains a blend of polydiorganosiloxane fluid and calcined clay. Zinc borate is disclosed as an additive to impart improved flame drip properties. U.S. Pat. No. 5,266,618 disclosed a flame-retardant resin composition that contains polycarbonate resin, an optional graft polymer, a phosphorus compound, a boron compound, and polyorganosiloxane. A thermoplastic molding composition that contains polycarbonate, vinyl copolymer, graft polymer, and a finely divided compound selected from the group consisting of zinc sulfide, zinc phosphate, zinc borate and zinc sulfate is disclosed in U.S. Pat. No. 6,596,800 to exhibit improved mechanical properties.
Currently pending patent application Ser. No. 11/713,352, filed Mar. 2, 2007 assigned to the present assignee disclosed compositions containing presently relevant components.